Application of Biobased Substances in the Synthesis of Nanostructured Magnetic Core-Shell Materials

We propose here a novel green synthesis route of core-shell magnetic nanomaterials based on the polyol method, which uses bio-based substances (BBS) derived from biowaste, as stabilizer and directing agent. First, we studied the effect of BBS concentration on the size, morphology, and composition of magnetic iron oxides nanoparticles obtained in the presence of BBS via the polyol synthesis method (MBBS). Then, as a proof of concept, we further coated MBBS with mesoporous silica (MBBS@mSiO2) or titanium dioxide (MBBS@TiO2) to obtain magnetic nanostructured core-shell materials. All the materials were deeply characterized with diverse physicochemical techniques. Results showed that both the size of the nanocrystals and their aggregation strongly depend on the BBS concentration used in the synthesis: the higher the concentration of BBS, the smaller the sizes of the iron oxide nanoparticles. On the other hand, the as-prepared magnetic core-shell nanomaterials were applied with good performance in different systems. In particular, MBBS@SiO2 showed to be an excellent nanocarrier of ibuprofen and successful adsorbent of methylene blue (MB) from aqueous solution. MBBS@TiO2 was capable of degrading MB with the same efficiency of pristine TiO2. These excellent results encourage the use of bio-based substances in different types of synthesis methods since they could reduce the fabrication costs and the environmental impact.